This study is a continuation of the Cardiovascular Health in Children (CHIC I) study, a randomized field trial conducted in 21 rural and urban elementary schools. In CHIC I the investigators tested the short-range (Post 1) and one year, mid- range (post 2) effects of interventions designed to reduce cardiovascular disease (CVD) risk factors in preadolesents. The interventions were: (1) a large group intervention taught by elementary school teachers and physical educators, (2) a small group intervention taught by nurses and physical educators given only to those who had one or more risk factors identified at pretesting. A control group received only feedback about the results of the physiologic testing. Subjects included 2,207 3rd and 4th graders at Pre test, 2,109 at Post 1, and 1,820 at Post 2. The racial distribution of the sample was almost identical to that of the state: 76.4% of the subjects were white, 19.4% African American, 4.2% other. The investigators found a high prevalence of obesity and physical inactivity, as well as high cholesterol levels and low aerobic capacity, particularly in rural black children. The short-range effects of the intervention are promising: both the large group and the small group interventions were successful in improving the health behaviors and CVD risk profiles of the subjects. Improvements in cholesterol and knowledge were still present at Post 2 in the large group subjects. The principal investigators now propose to follow the CHIC I subjects for 4 years, to determine the effects over time of the interventions used in CHIC I. The investigators will include all variables measured in CHIC I and add a lipid profile and an assessment of pubertal status. Further, the investigators will determine the natural history of CVD risk factors and aerobic capacity by following the CHIC I control subjects and additional control subjects through early and mid adolescence, examining the effects of pubertal level. The investigators will compare the prevalence of CVD risk factors in rural and urban areas using an ethnically diverse sample of subjects in early and middle adolescence. In CHIC I, although both interventions were successful in improving short range risk factor status, the large group intervention was cheaper, reached more youth, and was more effective in rural locales and with lower SES subjects. However, the Principal Investigators do not know which aspect of the intervention, knowledge or physical activity, was essential, nor do the investigators know if 3rd and 4th graders were the optimal timing for the intervention. Thus, the proposed study will focus on the large group intervention approach. The principal investigators will test the differential effects of both aspects of the large group intervention, classroom teaching and/or physical activity, using a randomized, 2X2 factorial design in eight rural middle schools. No schools or adolescents who participated in CHIC I will be included. By testing the intervention in 6th - 8th grades, the investigators will be able to compare the efficacy of the elementary vs. middle school interventions.